An Otto cycle (non-ideal) engine has 8 cylinders with a total displacement of 1200 cm3 and a low compression ratio of 8:1. The air entering the engine is at 27oC and 100 kPa. The fuel-air mixture during combustion releases 1500 kJ per kg of air of heat when the engine is under a load and running at 2200 rpm. Assuming that the compression and expansion processes are polytropic with polytropic indexes of 1.15 and 1.20, respectively, and taking cv = 0.718 kJ/kgK throughout the entire cycle.

Question 1
What are the maximum pressure and maximum temperature of the cycle?

a. 6,783.60 kPa; 2,543.85 K
b. 6,663.86 kPa; 2,498.95 K
c. 7,063.88 kPa; 2,648.96 K
d. 6,916.46 kPa; 2,593.67 K

Question 2
What are the entropy changes during the compression and expansion processes?

a. -0.2982 kJ/kgK; 0.2235 kJ/kgK
b. -0.1489 kJ/kgK; 0.0742 kJ/kgK
c. -0.3728 kJ/kgK; 0.2982 kJ/kgK
d. -0.2235 kJ/kgK; 0.1489 kJ/kgK

Question 3
What is the net work output per cylinder?

a. 0.1825 kJ
b. 0.1741 kJ
c. 0.2011 kJ
d. 0.1915 kJ

Question 4
What is the total power output of the engine?

a. 51.1 kW
b. 59.0 kW
c. 53.5 kW
d. 56.2 kW